[1] A cluster of three small maar craters like these is unique in the Auckland volcanic field.

They could have been associated with the eruption of nearby Matukutureia (also known as McLaughlin's Mountain) but this is speculation at present.

The cluster is composed of three maars, encircled by tuff cones that over tens of thousands of years have been partly breached and eroded by runoff from the small freshwater lakes appearing in the craters shortly after the eruption.

Due to the maars' very gentle rise over the otherwise level terrace of Pleistocene age, their volcanic origin had not been recognised earlier.

[3] Puhinui Arena Crater is breached on both the west and east sides.